Evaporator



June 25, 1929.

T. SHIPLEY EVAPORATO Filed Jan 2l, 1927 3 sheets-sheet 2 F E 7N 2 E a.ll-.lner 1929. I T SHIPLE'Y .A 1,718,312

i EVAPORATOR Filed Jan. 21; 1927 s sheets-sheet 5 @ktm/naga,

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Patented June 25, 1929.

UNITED STATES PATENT oFFicE.

THOMAS SHIPLEY, OF YORK, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO YORK ICE MACHINERY CORPORATION, OF YORK, PENNSYLVANIA, A CORPORA-TION OF DELAWARE.

EVAPORATOR.

Application filed January 21, 19%?. Serial N'o. 162,574.

This invention relates to refrigeration, and particularly to theconstruction and arrangement of the evaporators. In the past theadvantage of operating an evaporator flooded was fully understood, butefforts so to operate them have not proved uniformly successful and theinstallations have generally been limited to cases Where some type ofreceiver could be located above the evaporator and then feed it bygravity. A known arrangeinent is to make use of what is termed a suctiontrap as the reservoir Which feeds the coils, the separation of the vaporand the return of the liquid to the suction trap occurring through. theaction of gravity.

The purpose of the present invention iste produce an installation inwhich a plurality of units may be operated in parallel, may be defrostedindividually, may be adi usted individually for refrigerative effect,and in which substantially Hooded operation is insured, at all times.

The invention is particularly adaptable to hardening rooms for icecream, cold storagzfje, and similaiplants, and may be also einboifliedinbrine tanks for freezing ice in cans, brine coolers and the like.

It has heretofore been proposed to circulate liquid refrigerant throughan evaporator by a pump or equivalent means for the purpose ofmaintaininsij the evaporator substantially flooded, that is to say, tortue purper-:e of insuring that liquid refrigerant penetrates throughoutsubstantially the entire length oi? the evaporator. In such priordevices the receiver has been mounted above the evaporator, the ideabeing to keep the evaporator submerged in liquid by the existence of astatic head rather than by the action of the pump alone.

The pre-:ent case is directed to a particular ouilmdimcnt of thepositivo circulation idea, in which the refrigerant is so circulated'that it first enters the top of the evaporator, flows thence downwardlythrough the evaporator and returns from the evaporator with sutilcientvelocity to entrain with the liquid refrigerant the vapor formed inpassage through the evaporator. The receiver then acts as a suction trapin which the liquid and vapor separate, the vapor passing to the suctionline of the compressor and the liquid being recirculated by the pump.

This arrangement has various advantages. By making the circulationsufficiently rapid the liquid flow Will persist to the lower end of theevaporator' and Will be effective to entrain the evolved vapor and sweepit out of the evaporator even though a substantial portionof the crosssection of the evaporator be not lled with the liquid but remain clearfor the passage of the vapor. Another advantage is that When Athe pumpis shut down the evaporator drains, producing a condition favorable todefrosting of the evaporator on occasion.

In order to .insure equal distribution of the refrigerant not only todifferent evaporators of a group but also to each element, such as theindividual coils of each evaporatoi", use is made of overflowdistributors, so contrived as to insure ap} 3i'oxiiiiately uniformfeeding of all coils With liquid refrigerant. In order to regulate theaction of the evaporators, particularlywhere a` plurality of these areconnected up in parallel to a single compressor, use is made of a shortcircuiting lay-pass, by means of which effective circulation produced byt-he pump may be reduced at Will. This avoids any tlirottling of theliquid refrigerant in the circulating flor-J, and is an importantfeature, leading to smooth operation and close control.

aree practical embodiments of the invention are illustrated in theaccompanying drawings, in Which,

Fig. lA is an elevatiA lowing; ncctions for tivo hardenl ic; rooms, fedn'ieans of a single refrigerant cycle. In this view the compressor,condenser and receiver are indicated by conventional diagram, in orderto malte clear the pipe connections to 'these elements.

Fig'. 2 is a fragmentary view of one of' the coils of the evaporatorsillustrated in Fig. l.

3 is a transverse section of a distrib- "ating header on an enlargedscale, showing the eonstructbn of the flow distributors.

Fig. a a diagrammiatie elevation showing; the application of theinvention to cold storage rooms.

Fig. 5 a diagrammatic section showing the application of the inventionto a brine cooler.

Referring first to Figs. l, Q and 3, 6 represents a liquid cooling trapto Which liquid and its connections;

refrigerant comes by way of the pipe 7 and float valve 8 from a highpressure receiver. The purpose ol the float valve S is to maintain aconstant level within the liquidcooling trap 6. The valve 9 is anordinary stop valve in the liquid line.v The valve 10 controis an oildrain wherever it appears. Pipe 11 a suction connection Ifrom the trap 6and leads to the interstage connection of a two stage compressor. rlhiscoinpressor is indicated by the legend L P. appliedito its lowerpressure cylinder, and the legend -H. P. applied to the high pressurecylinder. The condenser is indicated by the letter l and the highpressure receiver by the legend H. P. R. It is to be understood that thecompressor is ot" any known variable capacity type. The compressor,condenser and receiver' are diagramniatically illustrated merely to showthe evaporator connections clearly. No novelty is claimed broadly forthe use oit a variable capacity compressor or for the particulararrangement ol the compressor- Iii 'fact these are subject toconsiderable cha-nge without depart ing from the inventive principlehere involved..

inasmuch as Fig. 1 shows two cooling rooms connected up in parallel, thesame Areference numerals will be applied to corresponding elements foreach room designates i generally by the legends Room A and Room B.

Pipe 12 leads from the trap 6 byl way of stop valve 13 and float valve14 to a suction trap 15. The purpose of the tloat valve lil to maintaina. constant levelotl liquid refrigerant in the trap 15. Leading from thebottom ot the trap 15 is a pipe 16 which is controlled by valve 17 andleads to a rotary pump 18 driven in vany desired manner. This pumpdischarges through valve 19 to a line 2() which leads to a distributinginanil'old 2l. A by-pass between the pipes 20 and 1G is controlled byby-pass valve 22. lior defrosting there is provided a hot gas connection23 controlled by a stop valve 24C, and since during the detrostingoperation the suction trap 15 might receive an excess of liquidrefrigerant, a reversed float valve 25 is provided. The reversed floatvalve 25 controls flow through the pipe connection 26 back to the cooler6.

Under normal conditions, as will be iinderstood, the trap 15 is at alower pressure than the trap 6, but, will be later ex- ]gilained, this`pressure relation is reversed during defrosting, and consequently thevalve 25 is provided and so arranged that it the level of liquid risesunduly high in the suction trap 15`it will open to permit flow throughthe pipe 26 back to the cooling trap 6.l This connection is providedwith a hand operated stop valve 27` for emergency use, and there is alsoa direct drain connection from the suction trap 15 to the pipe 2Gcontrolled by stop valve 28, which is normally closed.

The manifold 21 Aissimply a drum into which project distributing pipes29 having a row oll graduated perforations 30 so designed that as thelevel of the liquid refrigerant in the maniiold 21 rises, the rate ofoutflow will be increased to compensate. There are a plurality oic pipes29 in cach manifold 2l, one for each evaporator in the room. Thus in themanifold of Room A there are two sets of pipes and in Room ll there arethree sets of pipes. Each pipe 29 leads to the distriliiuting manifold31 ot an evaporator, consisting of a plurality of evaporator coils 32extending` in a sinuous path and discharging` at their lower ends intoan oil-take header 33. r1`he manifold 21, the manifold 31 and the header33 are all in communication with. each other through a pressureequalizing connection 3&1 which enters the manifolds 21 and 31 above theliquid level therein. The headers 33 are connected by an olf-take line35 with the suction trap 15 above the liquid level Vlihorein. The pipecontrolled by a stop valve 37 leads to the suction connection 38. Thisis connected, of course, to the low pressure stage of the compressor.

Under normal conditions of operation the following valves are open, 9,13, 17, 19, 27 and .37. .at the same time Vthe following valves areclosed, 10, 241- and 28. rThe valve 22 is wholly or partly openaccording to the rate of circulatory flow desired to maintain the propertemperature in the corresponding coils 32. li" it be desired to delrostthe coi of) and o( are closed, and the valve 24: is opeied to admit hotgas from the conii'iressor line to the pipe 20. At this time the pump 18is,o'f course, out ot operation. The eli'ect is to displace the liquidrefrigerant from the coils 32 causing it to flowl bach to the suctiontrap 15. Inverted iloat ralve 25 guardsagainst the accumulation ol anexcess of liquid refrigerant in the trap 15. .Any such excess isreturned to the trap G. This occurs be fause under the conditions jiustrecited trap l5 is at coinprcssor discharge pressure. Thon defrosting iscomplete the valve 211 is closed and the valves 37, 19 and 22 are againreopened and the pump 13 started.

lt will be observed that the coils of either room may be detrostedwithout interfering with ti e action of' the coils in the other room.and that the circulatory rate ior either room may be adjusted withoutaffecting the circulatory rate for the other room. Concurrentadjustments of the capacity of the4 in eitherroom, corresponding valves19,l

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single stage compression. Consequently there is :no liquid cooling trapand no reversed float 'valve connection. Instead, the liquid line 42from the receiver leads through a slop valve 43 to a float valve 44which controls the liquid level in the suction trap 45, essentiallyidentical in function to the suction trap 15. Liquid connection 46 leadsthrough valve 47 and circulating pump 48 from which connection to thedischarge line 5() is controlled by valve 49. The capacity of the pump48 is controlled by by-pass valve 52. Pipe 50 leads to a distributin,rheader There are a plurality of perforated distributor pipes 53, each ofwhich acts to control the flow of liquidA refrigerant to a correspondingcoil 54, of which only one is indicated in the drawing. These coils discharge into a manifold from which pipe leads to tra-p 45.

The suction connection is shown at 57 and is cont-rolled by a stop valve58. 59 is a valve controlling a hot gas connection for de frosting.

In Fig. 5 the application of the device to a brine cooler` for use inbrine tanks and elsewhere, is illustrated. In this figure the parts areall substantially similar to those shown :in Fig. 4 and are similarlynumbered. It will be observed that hot gas connections for defrostingare not necessary and are omitted. The brine tank is shown at 60.

In all three forms of the device, the flow to the various coils isequalized by an overllow or weir device, and the circulation isintentionally made so rapid that the vapor evolved in the evaporator cannot rise through the descending current of liquid rei fri gerard, but isswept downwardly and out with the liquid refrigerant, from which itseparates in the suction trap. The operation of the device, therefore7entails a delinitely maintained circulation which nmy actually be asmuch' as four or live times the quantity of liquid refrigerant which'can be evaporated in a single pass through the evaporator. This insuresa practically llooded condition of the evaporator at all times so thatthe entire surface of the eviq'iorator is rendered unusually effcctive.

What is claimed is,m

l. In a refrigeratingr system, the combination of a receiver and anevaporator con nccted to establish a closed circuit, the evaporatoroffering a plurality of flow paths in 'parallel arrangement; graduatedover-flow distril'iutingr means arranged to equalize the flow throughsaid parallel paths; power circulating means for circulatingr liquidrefrigerant in said circuit; a connection 'for withdrawingr vaporizedrefrigerant from the evaporator; and a connection for supplying liquidrcfrig'erz'int to said circuit.

2. In a refrigerating system, the combination of a .suction trap; anevaporator located in a position above the saine; connectionsestablishing a closed circuit from the lower portion of the suction trapto the top of the evaporator thence downward through the emporator andfrom the bottom of the evaporator to the suction trap; power circulatingmeans :for positively circulating liquid refrign erant in said closedcircuit, in a quantity substantially in excess of that evaporaible inthe evaporator whereby the vapor evolved in entrained by theolf-'llowing liquid refrigerant; a suction connection leading from Atheupper part of said suction trap; and a connection for supplying liquidrefrigerant.

In a refrigerating system, the combination of a receiver' and anevaporator connectu ed to establish a closed circuit, said evaporatorincluding a plurality of units connected in parallel, each unitcomprising?Y a plurality of tubes connected in parallel; primaryoverflow distributing means arranged to equalize `he flow of liquidrefrigerant to the various units; secondary over-flow dist-rilnitinglmeans arranged to equalize the flow to the various tubes of each unit;power circulating means for circulating liquid refrigerant through saidcircuit, under the control of said distributingr means; a connection forwithdrawing vaporized refrigerant from said evaporator; and a connectionfor supplying liquid refrigerant to said circuit.

4. The combination of a variable capacity compressor; a condenser towhich said compressor discharges; a plurality of evaporator' units eachincluding an evaporator and a suction trap connected to form a closedcircuit; power means corresliondinp,` to each circuit for circulatinglvolatile liquid refrigerant from the suction trap through the evaporatorand back to the suction trap; means for adjusting the circulatory rateof each power circulating means independently; vapor suction connectionsleading from the respective circuits to the suction of said compressor;and means for returning liquid refrigerant from said condenser to saidcircuits to compensate .for evaporation therein.

5. The combination of a varial'ile capacity compressor; a condenser towhich said com-- presser discharges; a plurality of evaporatorunits eachincluding an evaporator and a suction trap connected to form a closedcircuit; power means corresponding; to each circuit for circulatingvolatile yliquid refrigerant from the suction trap through theevaporator and back to the suction trap; an adjustable bypass betweenthe intake and discharge of each circulating means operable to vary thecirculatory rate through 'the corresponding evaporator;v vapor suctionconnections leading' from the respective circuits to the suction of saidcompressor; and means vculatory rate in one circuit independent of thatin another; a vapor suction connection from the various circuits to thecompressor; y

and automatic means for delivering liquid refrigerantfrom the condenserto said circuits at rates commensurate with the evaporation ofrefrigerant in such circuits.

7. The combination of a two-stage variable capacity comliircssor havingan inten stage passage; a condenser into which the high pressure stageof said compressor discharges; a primary refrigerant cooler; a feeddevice for delivering volatile liquid refrigerant from the condenser tosaid primary cooler; a vapor suction connection from said cooler to theinterstage passage of said compressor; an evaporator circuit consistinfrof an evaporator; a suction trap and a power circulating means forcirculating volatile liquid refrigerant from the trap through theevaporator and back to the trap; an automatic valve device for supplyingliquid refrigerant from said primary;

cooler to said trap at a rate commensurate with the evaporation in theevaporator; a vapor suction connection from the evaporator circuit tothe low pressure stage of the compressor; and means for varying thecirculatory rate `in said circuit.

8. The combination of a two-stage variable capacity compressor having aninterrstage passage; a condenser into which the high pressure stage ofsaid condenser discharges; a primary refrigerant cooler; automatic meansfor :feeding liquid refrigerant from said condenser to said primarycooler; a vapor suction connection from said.' primary cooler to theintel-stage passage of said compressor; a plurality of indelziendentevaporator circuits 'each consisting or an evaporator, a suction trap;and power operated means for circulating volatile liquid refrigerantfrom the trap through the corresponding evaporator and back to the trapindependent means for varying the circulatory rate of each circulatingmeans; and a vapor suction connection from each evaporator circuit tothe suction of the low pressure stage of the compressor,

9. The combination of a compressor; a condenser; a circuit including asuction trap; an evaporator mounted above said trap so as to drain tothe trap; and a power actuated circulating means arranged to drawvolatile liquid refrigerant from the trap anddis charge it through theevaporator and hack to the trap; a suction connection from the trap tothe suction of the compressor; a stop valve controlling said connection;and a valve controlled connection for delivering hot gas from thecompressor to said circuit.V

l0. The combination of a two-stage compressor; a .condenser into whichsaid com linessor discharges; a primary cooler; means for deliveringrefrigerant liquefied in the condenser 'to the primary cooler; a vaporsuction connection from the `primary cooler lto the interstage passageof said compressor;

an evaporator circuit consisting of a suction trap; an evaporatorarranged to drain by gravity into said trap and power actuatedcirculating means arranged to draw liquid from the trap and discharge itthrough the evaporator back to the trap; means for feedliquidrefrigerant from the primary cooler to the trap; a back-flow connectionfrom the trap to the primary cooler; liquid level control means foropeninff said backflow connection upon the existence of an unduly highlevel of refrigerant in the trap; a suction connection from the trap tothe low pressure stage suction of said compressor; a stop valvecontrolling said suction connection; and a valve controlled. connectionfor delivering hot gas from the coin:- pres to said evaporator circuit.

ll. ln a refrigerating device; the combination of a circuit including areservoir; an evaporator mounted above said reservoir so as to drainthereto, and a power actuated circulating means arranged to d 'awvolatile liquid refrigerant from the reservoir and discharge it downwardthrough the evaporator and back to the reservoir; a suction connectionfor withdrawing vapor evolved in the evaporator; a stop valvecontrolling said connection; and a valve-controlled connection fordelivering hot gas to said circuit.

l2. An evaporator comprising in combinaand to a point above tl liquidlevel therein;

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Suid projecting ends being. 'formed willi lateral perforzitions.

14;. An evaporator comprising in combinetion, e manifold adapted toreceive liquid refrigerant; and e plurality of tubes extending downwardfrom said manifold,tl1e upper ends of .en

id tubes projectingI through the bottoni of the manifold into the saineand to :i point above the liquid level therein, said projecting endsbeing formed with lateral 10 perforations graduated in size.

ln testimony whereof I have signed my nume to 'lliie' specification.

THOMAS SHPLEY.

